Line spacing mechanism



y 1939- E. BUSCHMANN 2,156,371

LINE SPACING MECHANISM Filed Nov. 16, 1937 2 Sheets-Sheet l l m/erzfor fuyen BuJcZmzrz-iz May 2, 1939. E. BUSCHMANN LINE SPACING MECHANISM Filed Nov.- 16, 1957 2 Sheets-Sheet 2 [771 872 for:

Patented May 2, 1939 LINEv SPACING MECHANISM Eugen Buschmann, Chemnitz, Germany, assignor to Wanderer-Werke vorm. Winklhofer &

J aenicke Akt.-Ges., many Siegmar-Schonau, Ger- Application November 16, 1937, Serial No. 174,857 In Germany November 19, 1936 3 Claims. (Cl. 197-414) This invention relates to a line spacing mechanism for the platen rolls of writing machines having a slide carrying a line spacing pawl and in which the beginning of engagement of said pawl with the ratchet wheel of the platen roll can be adjusted by a regulator in order to produce different amounts of line spacing.

In known line spacing'mechanisms of this kind the regulator is connected through suitable transmission parts with a stop which actuates the line spacing pawl during line spacing. Since the line spacing pawl has to be .returned by the stop to its position of rest during the return movement of the slide whereby impact of said pawl against the stop takes place, the transmission has to include retaining means for preventing unintended shifting of the stop and of the regulator. This leads to complication of the mechanism and a difiicult construction.

Objects of the present invention are to overcome this disadvantage and to provide a line spacing mechanism of this kind having an easy regulation of line spacing distances, together with cheapness of manufacture, simplicity of construction, and ready interchangeability of the different parts.

These objects are achieved according to the present invention which consists in combining the regulator and the stop member which actuates the line spacing pawl, into a single unit such that both these parts perform the same movements, this unit being locked by a latch means which is released during the regulating operation and which is automatically engaged on completion of the said operation.

A mechanism according to the invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is an end elevation of the mechanism in position of rest, set for a spacing of two lines,

Fig. 2 is a similar view of the mechanism, in an intermediate position,

Fig. 3 is a similar view of the mechanism in the end position,

Fig. 4 is a plan View of the mechanism in the end position,

Fig. 5 is an end view of the mechanism in the end position, with the line spacing pawl set to inoperative position,

Fig. 6 is a vertical section on line 66 of Fig. 4, on a larger scale, and

Fig. '7 is a section similar to Fig. 6 showing the stop member in tilted position.

On the shaft 3 of the platen roll, not illus- 65, trated, are fixed the usual line spacing feed ratchet wheel 5, and hand knobs 2 of which only the one on the left-hand side of the machine is shown in Fig. 4. On actuation of the line spacing mechanism the teeth 4 of the ratchet wheel 5 are engaged by the tooth 29 of the line spacing pawl |3 whereby the wheel and shaft 3 are rotated. This causes the platen roll to be advanced an amount corresponding to the setting of the line spacing regulator. The pawl I3 is pivotally mounted on a pin 27 on a slide 20 in the usual manner. A spring 28 is associated with pawl l3 and tends to rotate the latter in a direction to engage the ratchet wheel 5. The tail end- IQ of the pawl I3 is urged against a cam stop l2 by the action of the spring 28. The slide 20 is slidably mounted on a carrier plate I by means of pins 2| which extend through slots 22 of the slide. Between a lug 25 of the slide 20 and an ear 23 mounted on one of the pins 2| there is disposed a spring 26 for returning the slide to the position of rest in which it is retracted from the ratchet wheel. Spring 26 which is shown as a compression spring, is held straight by means of around bar 24 fixed in the lug 25.

Slide 20 carries a fixed tooth 3!], which when the slide is in its end position (Fig. 3) engages between teeth 4 of the ratchet wheel 5 and thereby limits the stroke of the slide 20 and prevents the ratchet wheel 5 from undesired further rotation, for example due to momentum. Slide 20 is shifted from the position of rest of Fig. 1 to the end position as shown in Figs. 3 and 4 by actuation of a lever 3| to the right (Fig. 4). Lever 3| is provided with a pin 42 engaging in a slot 43 of an intermediate bell crank lever 38, the arrangement being such that the intermediate lever 38 is rotated about its pivot 4| in a clockwise or right-hand direction (Fig. 4)- upon displacing lever 3| about its pivot 32 in a counterclockwise direction. A roller 33 mounted on the end of the intermediate lever 38 bears, in this operation, against the lug 25 of the slide 20. The operating lever 3| may be connected by means of a rod or link 39 with another operating lever similar to lever 3| (not shown) arranged at the right-hand side of the platen roll frame I! whereby the line spacing mechanism can be selectively actuated by levers 3| at both the left and the righthand sides of the platen frame. The operating lever 3| as is usual also serves as a means to return the paper carriage to initial position after a line has been typed.

During the movement of the operating lever 3| to the right, the slide 20 is shifted to the end of its movement and then the paper carriage is shifted. A stop 44 determines the position of rest of the intermediate lever 38.

The line spacing mechanism also includes looking means for holding the ratchet wheel 5 against unintended rotation. As shown in Fig. 5 this locking means consists of a locking roller 34 mounted on a lever 35 and pressed by means of a spring 37 acting on the lever 35 into the gaps between the teeth 4 of the ratchet wheel 5.

The cam stop I2 which actuates the line spacing pawl 13 is connected to a slide block II and is preferably integral therewith as shown in Figs. 6 and 7. Slide block I! has directly connected thereto by means of a pair of screws l5, a regulator or setting member l0, which is provided with openings for the passage of said screws. These openings are conical, enabling the regulator or setting member Ii] to tilt from the vertical position as shown in Fig. 6 to an oblique position as shown in Fig. 7 against the action of springs It. On release of the regulator or setting member Hi it is returned to the vertical position by means of said springs IS. The face of the regulator or setting member Iii slides against the side wall of the carrier plate I. A pin 9 is fixed in the carrier plate I for engagement in one of a number of notches I6 in the regulator or setting member in. In the position shown in Fig. 6 the regulator or setting member ID is locked against movement. By tilting the regulator or setting member by hand into the position of Fig. 7, the same is moved out of engagement with pin 9 so that the regulator or setting member can be adjusted. In this adjusting movement the slide block I i together with the cam stop I2 is displaced in a direction at right angles to the axis 3 of the platen roller, the block I! sliding on guide surfaces of a slot 1 in the carrier plate I.

The notches iii are so formed that they also serve as indicators for the setting of the regulator member I9. For this purpose the notches are designated with numerals l4 corresponding to the number of spaces which will be provided between the lines. An index mark 8 on the carrier plate I indicates the notch in which the pin 9 is received.

In the movement of the slide 20 towards the ratchet wheel the line spacing pawl l3, by the action of the cam stop I 2 on its tail I9, is first prevented from engaging the wheel 5 under the action of the'spring 28, Fig. 1. On further movement of the slide 20 the tail i 9 slides over the inclined end surface of the stop l2, as shown in Fig. 2, in which position engagement of the pawl l3 with the ratchet wheel 5 begins. This engagement continues during the further movement of the slide 20 until the end position (Fig. 3) is reached, when the fixed tooth 30 also engages the ratchet wheel 5 and locks the same. According to the position of the regulator or setting member ID, and therefore of the stop l2, at a greater or lesser distance from the ratchet wheel 5, the pawl l3 will be allowed to engage with the wheel 5 during a longer or shorter travel of the slide 20 whereby a larger or smaller line spacing is effected.

The regulator or setting member l0 .according to the present invention may be adjusted to a position in which no engagement of the pawl l3 with the wheel 5 will take place. This condition is shown in Fig. 5 where the slide 20 is shown in its end position but with the tail l9 of the line spacing pawl l3 still held by the stop 12 in such a manner that the pawl tooth 29 cannot engage the teeth of the wheel 5. This setting which in Fig. 4 is indicated by the numeral 0 has the advantage of enabling the paper carriage to be shifted by lever 3| without any rotation of the platen roll taking place when such is desired. Such operation is required when for example matter has to be inserted in definite lines .and the setting of the platen roll by hand to the desired line has been efi'ected, or when for any reason the line spacing has been effected by hand, as for example in variable line spacing. In such conditions since the returning of the paper carriage is ordinarily effected by means of the line spacing lever, an unintended line spacing ordinarily would take place automatically.

The cam stop member l2 has its rear portion formed in the same way as its front portion which engages with the tail H] of the line spacing pawl 63. This makes it possible to use the same elements H, I2 when the line spacing mechanism is to be arranged at the right-hand end of the platen roll frame ll instead of at the left-hand end. The stop 12 is then so mounted that its heretofore rear part faces the ratchet wheel 5. Also the other parts of the line spacing mechanism are so arranged that they can be mounted on either the left or the righthand side of the carrier plate I and slide 20.

By attaching the said member I!) to the slide block H by means of screws I5, it is easy to remove the regulator member and replace it by another in which the notches I 6 have a different spacing. This makes it possible, if necessary using a different ratchet wheel 5 with different spacing of the teeth 4, to obtain line spacing steps of different magnitude.

I claim as my invention:

1. A line spacing mechanism for a platen roll of writing machines comprising a ratchet wheel adapted to rotate with the roll, a frame, a slide slidable on the frame, a line spacing pawl cooperating with the ratchet wheel and pivoted on said slide, a cam stop on said frame so arranged in the path of the pawl as to control its engagement with the ratchet wheel in a line spacing operation, a member movable with the cam stop as a unit to determine the beginning of engagement of said pawl with said wheel to regulate line spacing, said regulating member being exchangeably fastened to said stop, and latch means operable to release said unit from said frame during a setting movement of the regulating member, said latch means automatically locking the unit to the frame on completion of a setting movement and including a pin fixed in the frame and a series of notches in the regulating member selectively engageable by the pin and corresponding to different line spacings.

2. A line spacing mechanism for a platen roll of writing machines comprising a ratchet wheel adapted to rotate with the roll, a frame, a slide slidable on the frame, a line spacing pawl cooperating with the ratchet wheel and pivoted on said slide, a cam stop on saidframe so arranged in the path of the pawl as to control its ongagement with the ratchet wheel in a line spacing operation, a member movable with the cam stop as a unit to determine the beginning of engagement of said pawl with said wheel to regulate line spacing, latch means operable to release said unit from said frame during a setting movement of the regulating member, said latch means automatically locking the unit to the frame on completion of a setting movement,

and fastening means connecting the regulating member to the stop, said fastening means causing unitary movement of the stop and regulating member in a line spacing setting operation, but permitting tilting movement between said stop and member transverse to said unitary movement, to engage and release the latch means.

3. A line spacing mechanism for a platen roll of writing machines comprising a ratchet wheel adapted to rotate with the roll, a frame, a slide slidable on the frame, a line spacing pawl cooperating with the ratchet wheel and pivoted on said slide, a cam stop on said frame so arranged in the path of the pawl as to control its engagement with the ratchet wheel in a line spacing operation, a member movable with the cam stop as a unit to determine the beginning of engagement of said pawl with said wheel to regulate line spacing, latch means operable to release said unit from said frame during a setting movement of the regulating member, said latch means automatically locking the unit to the frame on completion of a setting movement, and said stop having a pair of oppositely directed pawl engaging surfaces enabling the stop to be used at either side of the machine.

EUGEN BUSCHMANN. 

